Zach opted out of reviewing right now, so I went ahead and pushed my builds to the GitHub repos so that AppVeyor can run.
It built and ran fine (which I'm not surprised about), but it was only 1-2 minutes faster on AppVeyor (which I _am_ surprised about).
Tcl/tk/tix take longer than that to build on my dev machine, as does OpenSSL, so I'm not sure how AppVeyor was getting them to build so quickly. But in any case, it is definitely faster now, and I suspect more for our devs than our CI. OpenSSL can also be more easily upgraded, and the entire library is now available via ctypes, so all up I think it's a win (+ssl and hashlib experts in case they disagree).
Anyone want to take a look at the change before I merge?